Disable new test on redefine-stress.

slicer/dexter crashes dealing with the test.

Test: 842-vdex-hard-failure
Change-Id: Ibfdb577357f4ed9f6dc70a76fc2e68708aa0a250
diff --git a/test/knownfailures.json b/test/knownfailures.json
index 32c9e69..542ef9a 100644
--- a/test/knownfailures.json
+++ b/test/knownfailures.json
@@ -544,6 +544,7 @@
             "674-hiddenapi",
             "690-hiddenapi-same-name-methods",
             "804-class-extends-itself",
+            "842-vdex-hard-failure",
             "921-hello-failure",
             "999-redefine-hiddenapi"
         ],